2c0558f635
Profile queries This PR implements the "profile queries" debugging feature described here: https://github.com/rust-lang-nursery/rust-forge/blob/master/profile-queries.md In particular, it implements the debugging flag `-Z profile-queries` FYI: This PR is my second attempt at pushing these changes. My original PR required a rebase; I have now done that rebase manually, after messing up with git's "interactive" rebase support. The original (now closed/cancelled) PR is this one: https://github.com/rust-lang/rust/issues/43156 r? @nikomatsakis